Gwyn, G4FKH discussed propagation predictions including the influence of the sun and its observable sunspots, A and K index values and their interpretation, the regions of the Ionosphere affecting radio propagation, and the sunspot cycles and their history since the 1950’s
Additionally he explained work he and others are doing on behalf of the RSGB to assess background noise levels over the HF spectrum and the realisation that these have increased in recent times.
This presentation marks the end of meetings for the Summer break. Club meetings will resume on 8 September.
G4YRF was the ‘fox’ and one minute in five transmissions started at 20:00 from Great Hill, off Lucas Way, Shefford. The first member on the scene was Paul, G1GSN at 20:30 followed 5 seconds later by Ian, G3ORG. There was a brief pause till Peter, M0CKA and Derek, M0DLM arrived at 20:40. All five members met again at the pub for a chat and a drink.
A nearly full house heard Paul Hyde explain that it was more than 83 years since Paul Jansky began investigating the static which was proving problematic to transatlantic radio telephony in 1929. Jansky had built a large receiving array to scan the skies in an attempt to find the source of the noise. Apart from static from thunderstorms there was an emission from the sky near the location of Sagittarius. Other astronomers couldn’t accept the finding, but in1940 another astronomer, Grote Reber ( W9GFZ) from Chicago published his findings from his 9 meter dish at 160MHz. Jansky and Reber went on to map the sky and the first survey was published in 1944. Radio Astronomy as we now know it was underway, except that findings made during ww2 were classified and many who worked in astronomy were put to work in Radar.
Paul detailed the work that continued during and after the war which improved reception and resolution. It was explained how several aerials could be used at once and the results joined in a Correlator, a powerful computer able to combine the signals into one output. More signal sources in space were found and investigated resulting in discoveries of Pulsars, Blazars, Quasars and Radio Galaxies. Doppler Shift was discovered and how to make use of the Hydrogen lines on the spectrum.
Paul pointed out that as of 2003, Astronomers knew that in the Universe Dark Energy amounted to 73% and Dark Matter to about 22%, which leaves us knowing about the remaining 4%!